Hepatic Encephalopathy

Decline in brain function that occurs as a result of severe liver disease (cirrhosis)

Pathophysiology

1. Liver detoxification function is compromised by cirrhosis

2. This leads to excess ammonia in the systemic circulation

3. The ammonia reaches the brain where it is converted into glutamate by the astrocytes

4. This upsets the balance between glutamine and glutamate, putting an osmosic pressure on the astrocytes

5. The astrocytes swell, causing mental confusion

Clinical presentation

• Slow flapping tremor

• Confusion

• Presents similarly to alcohol withdrawal

Investigations

• Look for cause of cirrhosis

Management

• Treat cause of cirrhosis

• Lactulose to clear gut and reduce colonic transit time - less opportunity for bacteria to produce nitrogenous wastes

• Antibiotic e.g. rifaximin reduces bacterial load in the gut and changes the pH of the gut away from ammonia production

• If spontaneous consider transplantation - sign of advancing liver failure